The present invention relates to an extra-corporeal blood circulating apparatus, and more particularly to an extracorporeal blood circulating apparatus for exchanging gases in blood with an artificial lung, then delivering the blood into a blood reservoir from blood inlet ports which open at the bottom of the blood reservoir and lie horizontally, storing the blood temporarily in the blood reservoir, and thereafter supplying the stored blood to a human body.
When a thoracic operation, for example, is to be carried out on a patient, an extracorporeal blood circulating circuit is established using an artificial lung in which the blood is circulated for an exchange of carbon dioxide and oxygen. The blood is controlled at a prescribed temperature by a heat exchanger, and thereafter the gases are exchanged in the artificial lung. Then, the blood is temporarily stored in a blood reservoir for a steady supply of the blood. The blood is pumped into the patient under the operation at a constant pulse rate.
Blood reservoirs for use in extracorporeal blood circulation include a closed-type blood reservoir in the form of a soft bag for storing blood in an airtight condition and an open-type blood reservoir in the form of a hard housing for storing blood. The open-type blood reservoir is advantageous in that priming and confirmation of the stored amount of blood can easily be performed, and it would be easy to construct the blood reservoir as a unitary component of an artificial lung. Therefore, various extracorporeal blood circulating apparatus employing open-type blood reservoirs have been proposed.
FIG. 1 of the accompanying drawings schematically illustrates a extracorporeal blood circulating apparatus proposed by the applicant. The extracorporeal blood circulating apparatus comprises an artificial lung 2 and a blood reservoir 4 as an interconnected unitary system. The extracorporeal blood circulating apparatus is connected to the body of a patient through a pump (not shown) which supplies blood at a certain pulse rate. Blood B discharged from the human body is introduced into a heat exchanger and controlled at a prescribed temperature by warm or cold water. Thereafter, the blood B is fed from a blood supply port 6 into the artificial lung 2. The artificial lung 2 contains a multiplicity of hollow filamentary membranes 10 through which a gas A containing oxygen supplied from a gas inlet port 8 flows. The blood B, while passing around the hollow filamentary membranes, receives oxygen from the gas A and discharges carbon dioxide, and then flows upwardly through the artificial lung 2. The blood B then overflows the upper end of the artificial lung 2 into the blood reservoir 4 and is stored therein. After the exchange of oxygen and carbon dioxide, the gas A is discharged from the artificial lung 2 through a gas outlet port 12. The blood B stored in the blood reservoir 4 is supplied from a blood outlet port 14 into the human body.